Abstract：
The study investigates the therapeutic effects and mechanisms of ginsenoside Rg_1(GRg_1) on sepsis-induced acute lung injury(SALI). A murine model of SALI was created using cecal ligation and puncture(CLP) surgery, and mice were randomly assigned to groups for GRg_1 intervention. Survival and body weight changes were recorded, lung function was assessed with a non-invasive lung function test system, and lung tissue damage was evaluated through HE staining. The content and expression of inflammatory factors were measured by ELISA and qRT-PCR. Apoptosis was examined using flow cytometry and TUNEL staining. The activation and expression of apoptosis-related molecules cysteinyl aspartate specific proteinase 3(caspase-3), B-cell lymphoma-2(Bcl-2), Bcl-2 associated X protein(Bax), and endoplasmic reticulum stress-related molecules protein kinase R-like endoplasmic reticulum kinase(PERK), eukaryotic initiation factor 2α(eIF2α), activating transcription factor 4(ATF4), and C/EBP homologous protein(CHOP) were studied using Western blot and qRT-PCR. In addition, an in vitro model of lipopolysaccharide(LPS)-induced lung alveolar epithelial cell injury was used, with the application of the endoplasmic reticulum stress inducer tunicamycin to validate the action mechanism of GRg_1. RESULTS:: indicated that, when compared to the model group, GRg_1 intervention significantly enhanced the survival time of CLP mice, mitigated body weight loss, and improved impaired lung function indices. The GRg_1-treated mice also displayed reduced lung tissue pathological scores, a reduced lung tissue wet-to-dry weight ratio, and lower protein content in the bronchoalveolar lavage fluid. Serum levels of interleukin-6(IL-6), interleukin-1β(IL-1β), and tumor necrosis factor-α(TNF-α), as well as the mRNA expressions of these cytokines in lung tissues, were decreased. There was a notable decrease in the proportion of apopto-tic alveolar epithelial cells, and down-regulated expressions of caspase-3, Bax, PERK, eIF2α, ATF4, and CHOP and up-regulated expression of Bcl-2 were observed. In vitro findings showed that the apoptosis-lowering and apoptosis-related protein down-regulating effects of GRg_1 were significantly inhibited with the co-application of tunicamycin. Altogether, GRg_1 reduces apoptosis of alveolar epithelial cells, inhibits inflammation in the lungs, alleviates lung injury, and enhances lung function, possibly through the PERK/eIF2α/ATF4/CHOP pathway.
摘要：
研究人参皂苷Rg_1(GRg_1)对脓毒症急性肺损伤(SALI)的治疗作用及机制。使用盲肠结扎和穿刺（CLP）手术创建SALI的小鼠模型，将小鼠随机分组进行GRg_1干预。记录生存和体重变化，使用无创肺功能测试系统评估肺功能，HE染色评价肺组织损伤。ELISA和qRT-PCR检测炎症因子的含量和表达。使用流式细胞术和TUNEL染色检查细胞凋亡。细胞凋亡相关分子半胱氨酰天冬氨酸特异性蛋白酶3(caspase-3)的激活和表达,B细胞淋巴瘤-2(Bcl-2),Bcl-2相关X蛋白(Bax),和内质网应激相关分子蛋白激酶R样内质网激酶（PERK），真核起始因子2α（eIF2α），激活转录因子4（ATF4），使用Westernblot和qRT-PCR研究了C/EBP同源蛋白（CHOP）。此外,使用脂多糖（LPS）诱导的肺泡上皮细胞损伤的体外模型，内质网应激诱导剂衣霉素的应用验证了GRg_1的作用机制。结果：：表明，当与模型组相比时，GRg_1干预显著提高了CLP小鼠的存活时间,减轻体重，和改善受损的肺功能指标。GRg_1处理的小鼠肺组织病理评分也降低，肺组织湿干重量比降低，支气管肺泡灌洗液中的蛋白质含量较低。血清白细胞介素-6(IL-6)水平,白细胞介素-1β（IL-1β），和肿瘤坏死因子-α（TNF-α），以及这些细胞因子在肺组织中的mRNA表达，减少了。凋亡肺泡上皮细胞的比例显着下降，并下调caspase-3，Bax，PERK,eIF2α,观察到ATF4和CHOP以及Bcl-2的上调表达。体外研究结果表明，与衣霉素共同施用，GRg_1的凋亡降低和凋亡相关蛋白下调作用被显著抑制。总之,GRg_1减少肺泡上皮细胞凋亡，抑制肺部炎症，减轻肺损伤，增强肺功能，可能通过PERK/eIF2α/ATF4/CHOP途径。
